I have a 2004 Grand Prix GT and the heat only seems work blow warm air as I'm driving down the highway?
When ever I drive my car down the highway the heat seems to work fine, but when I come to a stop it starts to get cold and the temp gauge seems to go up as I slow down as well. Any ideas?
Sounds like a low coolant level or air trapped in the system.
I put some coolant in and it seemed to help. I checked it cold and it was low. Now I can hear a girling sound coming from the dash area when I'm driving slow or turning.
You could have air trapped in the system as well. It may take several efforts to get the air completely out. I've heard that parking with the car facing uphill and then running the engine and slowly topping up the radiator will sometimes get the job done. Give it a try.
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